Expanding the Mutation Spectrum in ABCA4: Sixty Novel Disease Causing Variants and Their Associated Phenotype in a Large French Stargardt Cohort

Here we report novel mutations in ABCA4 with the underlying phenotype in a large French cohort with autosomal recessive Stargardt disease. The DNA samples of 397 index subjects were analyzed in exons and flanking intronic regions of ABCA4 (NM_000350.2) by microarray analysis and direct Sanger sequencing. At the end of the screening, at least two likely pathogenic mutations were found in 302 patients (76.1%) while 95 remained unsolved: 40 (10.1%) with no variants identified, 52 (13.1%) with one heterozygous mutation, and 3 (0.7%) with at least one variant of uncertain significance (VUS). Sixty-three novel variants were identified in the cohort. Three of them were variants of uncertain significance. The other 60 mutations were classified as likely pathogenic or pathogenic, and were identified in 61 patients (15.4%). The majority of those were missense (55%) followed by frameshift and nonsense (30%), intronic (11.7%) variants, and in-frame deletions (3.3%). Only patients with variants never reported in literature were further analyzed herein. Recruited subjects underwent complete ophthalmic examination including best corrected visual acuity, kinetic and static perimetry, color vision test, full-field and multifocal electroretinography, color fundus photography, short-wavelength and near-infrared fundus autofluorescence imaging, and spectral domain optical coherence tomography. Clinical evaluation of each subject confirms the tendency that truncating mutations lead to a more severe phenotype with electroretinogram (ERG) impairment (p = 0.002) and an earlier age of onset (p = 0.037). Our study further expands the mutation spectrum in the exonic and flanking regions of ABCA4 underlying Stargardt disease.

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Ocular Characteristics of Patients with Leber Congenital Amaurosis 6 Caused by Pathogenic RPGRIP1 Gene Variation in a Chinese Cohort

Journal of Ophthalmology ◽

10.1155/2021/9966427 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Yumei Mao ◽

Yanling Long ◽

Bo Liu ◽

Qingling Cao ◽

Yijian Li ◽

...

Keyword(s):

Fundus Autofluorescence ◽

Chinese Patients ◽

Fundus Photography ◽

System Response ◽

Autofluorescence Imaging ◽

Genetic Characteristics ◽

Full Field ◽

Leber Congenital Amaurosis ◽

Gene Variation ◽

Rod System

Purpose. To delineate the clinical and genetic characteristics of Chinese patients with RPGRIP1-associated Leber congenital amaurosis 6 (LCA6). Methods. After screening 352 unrelated families with clinically diagnosed RP, five LCA6 patients with RPGRIP1 variations from unrelated Chinese families were identified. Full ophthalmology examinations, including decimal best-corrected visual acuity (BCVA), fundus photography, fundus autofluorescence imaging, spectral-domain optical coherence tomography (SD-OCT), full-field electroretinography (ffERG), multifocal electroretinography (mfERG), perimetry, and flash visual evoked potential (FVEP), were performed. Target next-generation sequencing (NGS) and Sanger sequencing were performed for the five patients to identify and to validate candidate disease-causing variants. Results. Five patients were molecularly diagnosed as the LCA6 associated with RPGRIP1 variation, with typical clinical characteristics including congenital night blindness, nystagmus, and visual defect, at an early age. Interestingly, LCA6 exhibited extensive clinical heterogeneity and the changes in the morphology and function were not completely consistent in the five LCA6 patients. Case 1 showed extensive inferior-nasal retinal atrophy with a corresponding area of hypofluorescence in fundus autofluorescence, and the fundus photograph was nearly normal in cases 2 and 3. The ERG results displayed a moderately reduced rod-system response in cases 1 and 2 and a significant reduced rod-system response in case 3. Both case 4 and case 5 showed mottled pigmentation in fundi and an unrecordable rod and cone-system response in ERG. Moreover, we identified eight compound variants and one homozygous variant in the five patients with RPGRIP1. Conclusions. This is the largest report focused on the clinical electrophysiological features of patients with associated LCA6 caused by the variation in the RPGRIP1 gene in the Chinese population with an enriched phenotypic and genotypic background of LCA6 to improve future gene therapies.

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Clinical Phenotype of PDE6B-Associated Retinitis Pigmentosa

International Journal of Molecular Sciences ◽

10.3390/ijms22052374 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2374

Author(s):

Laura Kuehlewein ◽

Ditta Zobor ◽

Katarina Stingl ◽

Melanie Kempf ◽

Fadi Nasser ◽

...

Keyword(s):

Visual Acuity ◽

Genetic Testing ◽

Retinitis Pigmentosa ◽

Fundus Autofluorescence ◽

Retinal Disease ◽

New Drugs ◽

Autofluorescence Imaging ◽

Full Field ◽

Tertiary Referral Center ◽

The Right

In this retrospective, longitudinal, observational cohort study, we investigated the phenotypic and genotypic features of retinitis pigmentosa associated with variants in the PDE6B gene. Patients underwent clinical examination and genetic testing at a single tertiary referral center, including best-corrected visual acuity (BCVA), kinetic visual field (VF), full-field electroretinography, full-field stimulus threshold, spectral domain optical coherence tomography, and fundus autofluorescence imaging. The genetic testing comprised candidate gene sequencing, inherited retinal disease gene panel sequencing, whole-genome sequencing, and testing for familial variants by Sanger sequencing. Twenty-four patients with mutations in PDE6B from 21 families were included in the study (mean age at the first visit: 32.1 ± 13.5 years). The majority of variants were putative splicing defects (8/23) and missense (7/23) mutations. Seventy-nine percent (38/48) of eyes had no visual acuity impairment at the first visit. Visual acuity impairment was mild in 4% (2/48), moderate in 13% (6/48), and severe in 4% (2/48). BCVA was symmetrical in the right and left eyes. The kinetic VF measurements were highly symmetrical in the right and left eyes, as was the horizontal ellipsoid zone (EZ) width. Regarding the genetic findings, 43% of the PDE6B variants found in our patients were novel. Thus, this study contributed substantially to the PDE6B mutation spectrum. The visual acuity impairment was mild in 83% of eyes, providing a window of opportunity for investigational new drugs. The EZ width was reduced in all patients and was highly symmetric between the eyes, making it a promising outcome measure. We expect these findings to have implications on the design of future PDE6B-related retinitis pigmentosa (RP) clinical trials.

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Structural evaluation in inherited retinal diseases

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2021-319228 ◽

2021 ◽

pp. bjophthalmol-2021-319228

Author(s):

Malena Daich Varela ◽

Burak Esener ◽

Shaima A Hashem ◽

Thales Antonio Cabral de Guimaraes ◽

Michalis Georgiou ◽

...

Keyword(s):

Adaptive Optics ◽

Fundus Autofluorescence ◽

Standard Of Care ◽

Laser Speckle ◽

Fundus Photography ◽

Laser Speckle Flowgraphy ◽

Retinal Diseases ◽

Autofluorescence Imaging ◽

Structural Evaluation ◽

Fundus Imaging

Ophthalmic genetics is a field that has been rapidly evolving over the last decade, mainly due to the flourishing of translational medicine for inherited retinal diseases (IRD). In this review, we will address the different methods by which retinal structure can be objectively and accurately assessed in IRD. We review standard-of-care imaging for these patients: colour fundus photography, fundus autofluorescence imaging and optical coherence tomography (OCT), as well as higher-resolution and/or newer technologies including OCT angiography, adaptive optics imaging, fundus imaging using a range of wavelengths, magnetic resonance imaging, laser speckle flowgraphy and retinal oximetry, illustrating their utility using paradigm genotypes with on-going therapeutic efforts/trials.

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Clinical and Haplotypic Variability of Slovenian USH2A Patients Homozygous for the c. 11864G>A Nonsense Mutation

Genes ◽

10.3390/genes10121015 ◽

2019 ◽

Vol 10 (12) ◽

pp. 1015 ◽

Cited By ~ 2

Author(s):

Andrej Zupan ◽

Ana Fakin ◽

Saba Battelino ◽

Martina Jarc-Vidmar ◽

Marko Hawlina ◽

...

Keyword(s):

Disease Severity ◽

Nonsense Mutation ◽

Age Of Onset ◽

Phenotypic Variability ◽

Fundus Autofluorescence ◽

Usher Syndrome ◽

Test Methods ◽

Rapid Screening ◽

Autofluorescence Imaging ◽

Phenotype Analysis

Purpose: to determine a detailed clinical and haplotypic variability of the Slovenian USH2A patients with homozygous c.11864G>A (p.Trp3955Ter) nonsense mutation and to develop sensitive, accurate and rapid screening test. Methods: Ten unrelated homozygous patients with detailed ophthalmological exam were included in our study. The High-Resolution Melting (HRM) method was developed for fast and reliable detection of the c.11864G>A mutation. Results: The c.11864G>A mutation represents the vast majority of pathogenic alleles in Slovenian USH2A-Usher syndrome population (84%). The median age of onset of nyctalopia was 16 years and all patients younger than 40 years had hyperautofluorescent rings on fundus autofluorescence imaging. The Kaplan Meier survival analysis showed a decline of central vision after the age of 40, with 50% patients reaching visual acuity (VA) ≤ 0.05 at the average age of 66 years visual field diameter less than 20° at the average age of 59 years. There was a relatively large phenotypic variability in the retinal and audiological phenotype. Analysis of the p.Trp3955Ter-homozygous patients revealed four different haplotypes, with the frequency of the most common haplotype ~65%. Disease severity did not correlate with the haplotype. Conclusions: According to the natural history of homozygous p.Trp3955Ter patients any therapy aimed to slow disease progression in these patients would be best started before the age of 40. Phenotypic variability suggests the presence of cis and/or trans factors outside the USH2A gene that are able to affect disease severity. High frequency of p.Trp3955Ter mutation in Slovenian USH2A gene pool appears to be initiated from different unrelated founders because of migrations from neighboring populations. The mutation on haplotype 2 seems to be the major founder allele.

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Prediction of Function in ABCA4-Related Retinopathy Using Ensemble Machine Learning

Journal of Clinical Medicine ◽

10.3390/jcm9082428 ◽

2020 ◽

Vol 9 (8) ◽

pp. 2428 ◽

Cited By ~ 2

Author(s):

Philipp L. Müller ◽

Tim Treis ◽

Alexandru Odainic ◽

Maximilian Pfau ◽

Philipp Herrmann ◽

...

Keyword(s):

Machine Learning ◽

Visual Impairment ◽

Age Of Onset ◽

Outer Nuclear Layer ◽

Stargardt Disease ◽

Full Field ◽

Corrected Visual Acuity ◽

Ensemble Machine Learning ◽

Prediction Of Function ◽

Patient Burden

Full-field electroretinogram (ERG) and best corrected visual acuity (BCVA) measures have been shown to have prognostic value for recessive Stargardt disease (also called “ABCA4-related retinopathy”). These functional tests may serve as a performance-outcome-measure (PerfO) in emerging interventional clinical trials, but utility is limited by variability and patient burden. To address these limitations, an ensemble machine-learning-based approach was evaluated to differentiate patients from controls, and predict disease categories depending on ERG (‘inferred ERG’) and visual impairment (‘inferred visual impairment’) as well as BCVA values (‘inferred BCVA’) based on microstructural imaging (utilizing spectral-domain optical coherence tomography) and patient data. The accuracy for ‘inferred ERG’ and ‘inferred visual impairment’ was up to 99.53 ± 1.02%. Prediction of BCVA values (‘inferred BCVA’) achieved a precision of ±0.3LogMAR in up to 85.31% of eyes. Analysis of the permutation importance revealed that foveal status was the most important feature for BCVA prediction, while the thickness of outer nuclear layer and photoreceptor inner and outer segments as well as age of onset highly ranked for all predictions. ‘Inferred ERG’, ‘inferred visual impairment’, and ‘inferred BCVA’, herein, represent accurate estimates of differential functional effects of retinal microstructure, and offer quasi-functional parameters with the potential for a refined patient assessment, and investigation of potential future treatment effects or disease progression.

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Best Clinical Practice for Age-Related Macular Degeneration Imaging

Journal of VitreoRetinal Diseases ◽

10.1177/2474126419834702 ◽

2019 ◽

Vol 3 (3) ◽

pp. 167-171 ◽

Cited By ~ 2

Author(s):

K. Bailey Freund ◽

Cynthia Toth ◽

Marco Zarbin

Keyword(s):

Optical Coherence Tomography ◽

Macular Degeneration ◽

Fundus Autofluorescence ◽

Age Related Macular Degeneration ◽

Fundus Photography ◽

Optical Coherence ◽

Autofluorescence Imaging ◽

Clinical Practices ◽

Age Related

Purpose: To identify best clinical practices for macular degeneration imaging. Methods: We reviewed best clinical practices for imaging patients with age-related macular degeneration. These recommendations are based on different levels of evidence (I-III). Results: The type of imaging needed depends to some degree on the clinical scenario: first visit vs follow-up visit vs poorly responsive patient. Conclusions: Imaging technologies that may be useful include optical coherence tomography, fundus photography, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, and optical coherence tomography angiography.

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Fundus Autofluorescence and Spectral Domain OCT in Central Serous Chorioretinopathy

Journal of Ophthalmology ◽

10.1155/2011/706849 ◽

2011 ◽

Vol 2011 ◽

pp. 1-4 ◽

Cited By ~ 11

Author(s):

Luiz Roisman ◽

Daniel Lavinsky ◽

Fernanda Magalhaes ◽

Fabio Bom Aggio ◽

Nilva Moraes ◽

...

Keyword(s):

Fluorescein Angiography ◽

Central Serous Chorioretinopathy ◽

Near Infrared ◽

Pigment Epithelium ◽

Fundus Autofluorescence ◽

Subretinal Fluid ◽

Spectral Domain ◽

Fundus Photography ◽

Cross Sectional ◽

Spectral Domain Oct

Background. To describe the standard autofluorescence (FAF), the near infrared autofluorescence (NIA) and optical coherence tomography (OCT) patterns in central serous chorioretinopathy, correlating them with fluorescein angiography.Methods. Cross-sectional observational study, in which patients with at least seven months of CSC underwent ophthalmologic examination, fundus photography, FAF, NIA, fluorescein angiography (FA), and spectral-domain OCT.Results. Seventeen eyes of thirteen patients were included. The presentation features were a mottled hyperFAF in the detached area and areas with pigment mottling. NIA images showed areas of hyperNIA similar to FAF and localized areas of hypoNIA, which correlated with the points of leakage in the FA. OCT showed pigment epithelium detachment at the location of these hypoNIA spots.Discussion. FAF showed increased presence of fluorophores in the area of retinal detachment, which is believed to appear secondary to lipofuscin accumulation in the RPE or the presence of debris in the subretinal fluid. NIA has been related to the choroidal melanin content and there were areas of both increased and decreased NIA, which could be explained by damage ahead the retina, basically RPE and choroid. These findings, along with the PEDs found in the areas of hypoNIA, support the notion of a primary choroidal disease in CSC.

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Clinical Heterogeneity in Autosomal Recessive Bestrophinopathy with Biallelic Mutations in the BEST1 Gene

International Journal of Molecular Sciences ◽

10.3390/ijms21249353 ◽

2020 ◽

Vol 21 (24) ◽

pp. 9353

Author(s):

Karsten Hufendiek ◽

Katerina Hufendiek ◽

Herbert Jägle ◽

Heidi Stöhr ◽

Marius Book ◽

...

Keyword(s):

Autosomal Recessive ◽

Age Of Onset ◽

Fundus Autofluorescence ◽

Serous Retinal Detachment ◽

Fundus Photography ◽

Macular Dystrophy ◽

Ophthalmological Examination ◽

Hyperreflective Foci ◽

Autosomal Recessive Bestrophinopathy ◽

Biallelic Mutations

Autosomal recessive bestrophinopathy (ARB) has been reported as clinically heterogeneous. Eighteen patients (mean age: 22.5 years; 15 unrelated families) underwent ophthalmological examination, fundus photography, fundus autofluorescence, and optical coherence tomography (OCT). Molecular genetic testing of the BEST1 gene was conducted by the chain-terminating dideoxynucleotide Sanger methodology. Onset of symptoms (3 to 50 years of age) and best-corrected visual acuity (0.02–1.0) were highly variable. Ophthalmoscopic and retinal imaging defined five phenotypes. Phenotype I presented with single or confluent yellow lesions at the posterior pole and midperiphery, serous retinal detachment, and intraretinal cystoid spaces. In phenotype II fleck-like lesions were smaller and extended to the far periphery. Phenotype III showed a widespread continuous lesion with sharp peripheral demarcation. Single (phenotype IV) or multifocal (phenotype V) vitelliform macular dystrophy-like lesions were observed as well. Phenotypes varied within families and in two eyes of one patient. In addition, OCT detected hyperreflective foci (13/36 eyes) and choroidal excavation (11/36). Biallelic mutations were identified in each patient, six of which have not been reported so far [c.454C>T/p.(Pro152Ser), c.620T>A/p.(Leu207His), c.287_298del/p.(Gln96_Asn99del), c.199_200del/p.(Leu67Valfs*164), c.524del/p.(Ser175Thrfs*19), c.590_615del/p.(Leu197Profs*26)]. BEST1-associated ARB presents with a variable age of onset and clinical findings, that can be categorized in 5 clinical phenotypes. Hyperreflective foci and choroidal excavation frequently develop as secondary manifestations.

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Near-infrared fundus autofluorescence imaging in a case of photic maculopathy

International Journal of Diagnostic Imaging ◽

10.5430/ijdi.v1n1p28 ◽

2014 ◽

Vol 1 (1) ◽

pp. 28

Author(s):

Alberto Neri ◽

Alessandra Protti ◽

Monica Camparini ◽

Claudio Macaluso

Keyword(s):

Near Infrared ◽

Imaging Modality ◽

Pigment Epithelium ◽

Fundus Autofluorescence ◽

Retinal Pigment ◽

Parallel Evolution ◽

Conventional Imaging ◽

Autofluorescence Imaging ◽

Rpe Cells

Herein we describe the characteristics of scanning laser ophthalmoscope imaging (SLO), and particularly of near-infrared fundus autofluorescence modality (IRAF), in photic maculopathy. IRAF visualizes selectively the melanin granules contained in the cells of the Retinal Pigment Epithelium (RPE), which are normally localized in the apical portion of RPE cells, a favorite target of the photic damage to the retina. In the present work we report a three-month follow-up of a case of photic maculopathy, showing that the retinal alterations found by IRAF precisely matched the retinal anomalies found by macular optical coherence tomography, and had a parallel evolution. We think that IRAF could represent a useful imaging modality, together with more conventional imaging, in the management of photic maculopathy.

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Prediction of causative genes in inherited retinal disorder from fundus photography and autofluorescence imaging using deep learning techniques

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-318544 ◽

2021 ◽

pp. bjophthalmol-2020-318544

Author(s):

Yu Fujinami-Yokokawa ◽

Hideki Ninomiya ◽

Xiao Liu ◽

Lizhu Yang ◽

Nikolas Pontikos ◽

...

Keyword(s):

Deep Learning ◽

Fundus Autofluorescence ◽

Genetic Diagnosis ◽

Fundus Photography ◽

Macular Dystrophy ◽

Test Accuracy ◽

Autofluorescence Imaging ◽

The Mean ◽

Fundus Photographs ◽

Retinal Disorder

Background/AimsTo investigate the utility of a data-driven deep learning approach in patients with inherited retinal disorder (IRD) and to predict the causative genes based on fundus photography and fundus autofluorescence (FAF) imaging.MethodsClinical and genetic data from 1302 subjects from 729 genetically confirmed families with IRD registered with the Japan Eye Genetics Consortium were reviewed. Three categories of genetic diagnosis were selected, based on the high prevalence of their causative genes: Stargardt disease (ABCA4), retinitis pigmentosa (EYS) and occult macular dystrophy (RP1L1). Fundus photographs and FAF images were cropped in a standardised manner with a macro algorithm. Images for training/testing were selected using a randomised, fourfold cross-validation method. The application program interface was established to reach the learning accuracy of concordance (target: >80%) between the genetic diagnosis and the machine diagnosis (ABCA4, EYS, RP1L1 and normal).ResultsA total of 417 images from 156 Japanese subjects were examined, including 115 genetically confirmed patients caused by the three prevalent causative genes and 41 normal subjects. The mean overall test accuracy for fundus photographs and FAF images was 88.2% and 81.3%, respectively. The mean overall sensitivity/specificity values for fundus photographs and FAF images were 88.3%/97.4% and 81.8%/95.5%, respectively.ConclusionA novel application of deep neural networks in the prediction of the causative IRD genes from fundus photographs and FAF, with a high prediction accuracy of over 80%, was highlighted. These achievements will extensively promote the quality of medical care by facilitating early diagnosis, especially by non-specialists, access to care, reducing the cost of referrals, and preventing unnecessary clinical and genetic testing.

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